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(Application filed Jan. 24. 1898.)

3 SheeisSheet 2.

(No Model.)

No. 613,755. Patented Nov. a, |898. E. BnooK.

FURNAQE.

(Application med Jan. 24, 1898.) (No Model.) 3 Sheets-Sheet 3.

ma Noms PETERS co. PHOTO-umu., wAswNGToN. o c

UNITED STATES PATENT OFFICE.

EDWARD BROOK, OF I-IUDDERSFIELD, ENGLAND.

FURNACE.

' SPECIFICATION forming part of Letters Patent No. 613,755,1dated November 8, 1898.

Application led January Z4, 1898. Serial No. 657,695. (No model.)

To tir/ZZ whom it may concern:

. Be it known that I, EDWARD BROOK, a subject of the Queen of Great Britain and Ireland, residing at Huddersfield, in the county of York, England, have invented Improvements in Furnaces, of which the following is a specification. p

This invention relates to externally and internally fired furnaces (such as those of steamgenerators) of the kind in which air is supplied under pressure to the ash-pit or airchamber (hereinafter called the ashpit) under the fuel bearer or bearers by steam-j et apparatus or other mechanical means; and it has for its object to provide in a simple and efficient manner, rst, for the passing of a portion of the air or blast in a regulated quantity from the said ash-pit over the dead-plate to the combustion chamber or space above the fire for the purpose of promoting or aiding combustion and preventing the formation of smoke; second, for automatically reducing or lowering the pressure of air in the ash-pit when the fire-door is, for stoking or other purposes, opened, thereby reducing the risk of flame being projected outward through the doorway; third, for admission to the combustion-chamber with blast from the ash-pit of a regulated current or currents of air from the external atmosphere, (induced by the chimneydraft,) and, fourth, in the case more particularly of externally-fired boilers to enable the furnace and ash-pit doors and other parts to be tted in a cheaper and simpler mannery than heretofore to the front plates or castings used to close the front end of the combustion-chamber and ash-pit and so as to lessen or obviate liability of such plates or castings, which are often of large size, being fractured through unequal expansion or contraction. For attaining these objects furnaces are constructed as I shall now proceed to describe by aid of the accompanying drawings, wherein- A Figure l shows, partly in front elevation and partly in crosssection on the linem of Fig. 2, Fig. 2 in longitudinal section on the line y y of Fig. l, and Fig. 3 in horizontal sectiongon the line 2 2 of Fig. l, a furnace embodying my invention applied to externally heat a steam generator. Fig. 4 shows in longitudinal section on the line y 'y' of Fig. 5, and Fig. 5 in front elevation,with part removed, the applia cation of my invention to an internally-ied steam-generator. Fig. G is a sectional detail view hereinafter referred to.

To attain the first, second, and third objects mentioned, the front of the ash-pit l-is closed by a plate or casting 2, in which is formed, below the level of the dead-'plate 3, a suitable opening 4, and the fire-door 5 is so constructed that when closed it will cover the said opening et and also will close the doorway 6 above and will provide a passage 7 between the ash-pit l and the combustion-chamber 8, the arrangement being such that, subject to the control of a valve 9, carried by the fire-door and capable of being opened and closed, as hereinafter mentioned, a portion of the air or blast admitted to the ash-pit can pass from the front end thereof through the recess or passage 7 in the fire-door 5 tothe combustion chamber or space 8 above the fuel when the fire-dooris closed, and upon opening the said door 5 the ash-pit will, through the opening 4 in its front plate or wall, be automatically placed in communication with the external atmosphere, so that the pressure in the ash-pit will then be reduced and the risk of flame [lashing out of the open doorway be lessened. v

In the example shown air is supplied to the ash-pit l by two sets of steam-jet apparatus or blowers, each comprising a conical air-induction pipe l0, into which a jet of steam is caused to pass from a steam-supply pipe l0, so as to induce air to flow through the pipe l0 into the ash-pit, as well understood, or any other known or suitable means may be used for supplying air to the ash-pit.

For the purpose of regulating the quantityT of or'arresting the air passing from the ashpit 1 to the combustion-chamber 8 and of also admitting a correspondingly-regulated cur-v rent or currents of air (induced by the chi'mA ney-draft) to the combustion-chamber from the external atmosphere there are provided a suitable opening ll in the furnace-door 5 and a valve arrangement comprising a part 9, which controls the passage 7 between the ashpit l and the combustion-chamber 8, and a part 9, which controls the air-opening ll, formed through the door.

In the arrangement shown in Figs. l to 5,

inclusive, the valve 9 9 is of L shape and is operated by a transverse shaft 12, able to be rotated in bearings 13, carried by the door 5, and provided with pinions 14, that gear with suitable teeth 15, formed with or attached to the valve, a knob or hand-wheel 1G (orknobs or hand-wheels) being provided, whereby the shaft 12 can be rotated. The valve 9 may, however, be used alone for controlling the passage 7, as shown in Fig. 6, the part 9 being then made in one piece with the fire-door, in which will be a horizont-al slit, through which the said Valve can move, or a pivoted ap-valve 9b, worked by a lever or handwheel 9c, as indicated in dotted lines, may be used.

In some cases there might obviously be more than one opening 4L in the front of the ash-pit 1, and the door 5 might be so constructed as to afford more than one passage 7 between the ash-pit 1 and the combustionchamber S, and more than one controllingvalve 9 or 9 9:, adapted to serve the purposes above mentioned, might be provided in one door.

'lhe plate or casting 2, forming the front of the ash-pit 1, may advantageously be made in one with the plate or casting closing the front end of the combustion-chamber S and may be formed with an opening 17, normally closed by a door 18, for affording access to the ash-pit. This plate or casting 2, in addition to carrying the iire and ash-pit doors 5 and 1S, respectively, carries the air-supply apparatus 10 10a. ternally heating steam-gen erators, and for regenerative, puddling, and like furnaces, the plate or casting 2 is, according to this invention, in order to attain the fourth object hereinbefore mentioned, made separate from the plate or casting 19, used to form the front end of the furnace, as shown in Figs. 1, 2, and 3, the said plate or casting 2 being arranged to enter a correspondiugly-shaped hole in the plate or casting 19 and being formed with a iiange 2, by which it can be secured by bolts and nuts or studs at 19n to the plate or casting 19. As will be readily understood, by this arrangement all the planing and facing and also all the drilling, eX- cept the holes required in the plate or casting 19 for the bolts or studs at 19, can be done on the comparatively small and portable plate or casting 2, and as the main portion of the heat of the furnace about the doorway comes on the fire-door and such separate plate or casting 2 the main plate or casting 19, which is comparatively large and expensive, is prevented from being subjected to excessive local expansion and contraction such as is liable to fracture it.

What I claim is- 1. In a furnace, a closed ash-pit; a solid dead-plate; means for supplying air under pressure to the ash-pit; an airway from the front end of the ash-pit past the front end of the dead-plate to the front end of the com- In the case of furnaces for exbustion-chamber; means for controlling the' effective area of said airway; and means for opening the said airway to the open air all combined and operating substantially as described.

In a furnace, an ash-pit with an opening in its front end under the dead-plate; asolid dead-plate; a combustion-chamber open at its frontend; a door covering the front end of the combustion-chamber and formed with an extension recessed in its inner side which, when the door is closed, covers the opening in the front end of the ash-pit and forms an air-passage from the ash-pit to the combustion-chamber substantially as and for the purpose described.

4c. In a furnace of the kind herein referred to,the combination of a plate arranged to close the front end of the ash-pit and having an aireXit opening therein below the dead-plate of the furnace, a fire-door formed with an extension that is recessed on its inner side and which, when the door is closed, is adapted to cover said air-exit opening and form a passage whereby air escaping through said exit opening will be directed into the front end of said combustion-chamber above said deadplate, and which, when the door is open, will leave said exit-opening in direct communication with the external atmosphere, and means carried by said fire-door for controlling the flow of air through said passage, substantially as herein described for the purpose specified.

5. In a furnace of the kind herein referred to,the combination of a plate arranged to close the front end of the ash-pit and having an aireXit opening therein below the dead-plate of the furnace, a fire-door formed with an opening through which air can pass direct from the external atmosphere to the combustionchamber, and with an extension that is recessed on its inner side and is so arranged that when said door is closed the recessed part of its extension will cover the air-exit opening in the plate and form a passage Whereby air escaping through said air-exit opening will be directed into the front end of said combustion-chamber above said dead-plate, and a valve arrangement carried by said firedoor and adapted to control the 110W of air through both of the air-passages in said door, substantially as herein described.

G. In a furnace adapted for externally heating a steam-generator, a compound front plate comprising a stationary main plate in one or more parts, and a supplementary plate detachably connected to said main plate, adapted to close the front ends of the combustionchamber and ash-pit and formed with an air- IOO IIO

exit opening below the dead-plate of the furnace, and a re-door hinged or jointed to said supplementary plate and formed With an eX- tension adapted to cover and uncover said air-exit opening in the supplementary plate when the door is closed and opened respectively and having at its inner side a recess or cavity whereby air can pass from the front end of ash-pit to the front end of the com bastion-chamber when said door is closed, substantially as described.

7. In a furnace of the kind herein described, the improved front plate comprising the stationary main plate having an opening therein opposite the combustion-chamber and ash-pit, and the supplementary plate detachably xed to said main plate over said opening .and formed with a re-door opening controlled by a fire-door, an ash-pit opening normally closed by a separate door, an air-exit opening in communication With the ash-pit, and one or more air-inlet openings with means for supplyin g air under pressure to said ash-pit, said lire-door being formed With a recessed extension adapted, when the door is closed, to form an air-passage from said air-exit opening to the front end of said combustion-chamber, and provided with a Valve adapted to control said air-passage, substantially as herein described.

Signed at 2 Popes Head Alley, Cornhill, in the city of London, England, this 3d day of January, 1898.

EDWARD BROOK.

Witnesses:

Pnncv E. MATTocKs, WM. O.Y BROWN. 

